Technologies of this type may be seen in e.g. U.S. Pat. Nos. 9,148,729, 8,170,237, US20040179703, US2014/0086433, and US20150137834.
In a first aspect, the invention relates to a sensing system comprising:                a transducer having a first output terminal and a second output terminal,        a first voltage supply configured to supply a first voltage to the first output terminal,        an amplifier having an amplifier input and an amplifier output,        a connection element connecting the first output terminal to the amplifier input, the connection element comprising an impedance element connected also to a predetermined voltage, the impedance element having:        a first impedance, when a voltage over the impedance element is below a threshold voltage and        a second impedance, lower than the first impedance, when a voltage over the impedance element exceeds the threshold voltage, the first impedance exceeding the second impedance and        a filter circuit blocking DC but transferring AC, the circuit connected to the amplifier output configured to feed an AC signal to the second output terminal,where the amplifier has a negative amplification with an absolute value higher than or equal to the first voltage divided by the threshold voltage.        